Love this game, but one of the things that always seemed to be missing was the fact you knew who the Big Bad was from the get go. Mythos stories were always stories of investigation.
Here's a scenario that makes the Ancient One an unknown factor. I'll playtest it out some, this is the first draft.
There's 10 Slumber Cards (basically the random affects the hidden Ancient One has on the game) and 10 Worshippers cards (how they affect the Cultists and monsters). Those are all done, I'll post them as I have time.
Please excuse the formatting issues, still getting used to working with the limitations of this site.
A link to the whole image for printing or ease of reading: